Long-chain alcohols have many uses in cosmetics and personal care. One such example is idebenone; a potent anti-oxidant shown to reduce skin roughness, fine lines and wrinkles. In addition, idebenone may improve photo-damaged skin (McDaniel, D. H. et al. Journal of Cosmetic Dermatology 2005, 4 (3), 167-173). This material has also been claimed to induce protective and regenerative effects (U.S. Pat. No. 6,756,045), reduce skin hyperpigmentation (US Patent Publication 2005/0175559), and to reduce irritation and/or inflammatory reaction in human skin (US Patent Application Publication 2005/0197407).
Idebenone (2-(10-hydroxydecyl)-5,6-dimethoxy-3-methylcyclohexa-2,5-diene-1,4-dione) can be oxidized to the corresponding acid (idebenone acid; 10-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)decanoic acid). Ester derivatives of idebenone acid may improve the physical properties of this orange solid. In addition, depending upon the nature of the ester, esters of idebenone acid may or may not readily hydrolyze in the skin to afford idebenone acid along with the corresponding alcohol; depending upon the alcohol, hydrolysis product may be beneficial too.
The classical chemical preparation of esters such as idebenone acid esters involves either the reaction of an alcohol with the idebenone acid, an idebenone acid halide, or idebenone acid anhydride. Methods to prepare esters can be conducted using mild to harsh chemical methodology and/or via enzymatically. There are limited reports of short-chained idebenone acid esters (i.e. methyl, ethyl and benzyl; Okamoto, K. et al. Chem. Pharm. Bull. 1982, 8, 2797-2819; and Okamoto, K. et al., Biochim. Biophys. Acta. 1982, 682, 145-151). However, there lacks idebenone acid esters derived from longer-chained alcohols. A long-chain ester analog may be more physiologically compatible and less irritating to skin than idebenone acid (Schürer, 2002, Contact Dematitis 47: 199-205; Kojima et al., 1998, Altern. Animal Test. Exper. 5: 201-210). Hence, compositions based on esters of 4,5-disubstituted-oxy-2-methyl-3,6-dioxo-cyclohexa-1,4-dienyl alkyl acids may reduce unwanted side effects (i.e. skin irritation). It is the object of this invention to provide such compounds and compositions.